🐛(main): fix file extension deal bug

Author: W-Mai

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "icu_tool"
-version = "0.1.11"
+version = "0.1.11-1"
 edition = "2021"
 authors = ["Benign X", "W-Mai"]
 homepage = "https://github.com/W-Mai/icu"

res/img_0.png res/img_0.index8.pngres/img_0.png renamed to res/img_0.index8.png

@@ -252,7 +252,7 @@ fn deal_path_without_extension(
     .ok_or("Unable to get parent folder of input file")?;
 
     let file_name = file_path.file_name().unwrap_or_default();
-    let output_file_name = Path::new(file_name).with_extension("");
+    let output_file_name = Path::new(file_name).with_extension("PLACEHOLDER");
     let mut output_file_path = file_folder.join(&output_file_name);
 
     if let Some(output_folder) = output_folder {